It is known to use a needling table of circular type for fabricating annular textile structures that are to constitute the fiber reinforcement of annular parts made of composite material, in particular brake disks, such as disks made of carbon/carbon (C/C) composite material for airplane brakes.
Typically, a circular needling table comprises a horizontal top on which an annular fiber preform is placed, drive means (usually friction drive means) for driving the fiber preform in rotation around a vertical axis of rotation, and a needling device having a needling head that occupies an annular sector of the table top and that is driven with vertical reciprocating motion relative to the table top.
The annular fiber preform is laid on the top of the needling table in mutually superposed layers. The fiber preform is driven to rotate about the vertical axis and it is struck by the needling head whenever it passes under the needling head so as to bond together the various layers. The table is caused to move downwards in steps as additional layers of the fiber preform are put into place and needled. Reference may be made to Document WO 02/088451, which describes an embodiment of such a needling table.
The mechanical characteristics of the final product as obtained in this way depend strongly on the real density of needling used in the fiber reinforcement. This real density of needling depends in particular on the density of needling per unit area, on the penetration depth of the needles, on the size of the downward step of the table, and on functional characteristics of the needles.
With present needling methods, it is sometimes difficult to obtain good uniformity of needling over the entire surface area of the fiber preform. In addition, the expansion of the fibers of the fiber preform that is obtained as a result of passing the needles is not always optimized.